From c8118438ae4ad477f8b4f7c969e2c16b892a0d8f Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Sat, 16 Apr 2022 17:07:39 +1000
Subject: [PATCH] Do not update frame position until local image is found

---
 Tests/images/comment_after_last_frame.gif | Bin 0 -> 1625 bytes
 Tests/test_file_gif.py                    |  27 ++++++++++++++--------
 src/PIL/GifImagePlugin.py                 |   4 ++--
 3 files changed, 19 insertions(+), 12 deletions(-)
 create mode 100644 Tests/images/comment_after_last_frame.gif

diff --git a/Tests/images/comment_after_last_frame.gif b/Tests/images/comment_after_last_frame.gif
new file mode 100644
index 0000000000000000000000000000000000000000..9f5c7b8da471dfe3f29d4578c83d145b81dc69dc
GIT binary patch
literal 1625
zcmZ?wbhEHbWMp7uXlED&qaiS&LqPFAx1VcBu(M-;tC5}oGb1AdgAOP_K-q(VgN1>S
jg@r-!AA53sZf<H`2|^B-bp%Irz>Ru-WQPD|-mnG$b$}1h

literal 0
HcmV?d00001

diff --git a/Tests/test_file_gif.py b/Tests/test_file_gif.py
index dffd1006f2f..d177520e2cb 100644
--- a/Tests/test_file_gif.py
+++ b/Tests/test_file_gif.py
@@ -341,16 +341,23 @@ def test_seek_rewind():
             assert_image_equal(im, expected)
 
 
-def test_n_frames():
-    for path, n_frames in [[TEST_GIF, 1], ["Tests/images/iss634.gif", 42]]:
-        # Test is_animated before n_frames
-        with Image.open(path) as im:
-            assert im.is_animated == (n_frames != 1)
-
-        # Test is_animated after n_frames
-        with Image.open(path) as im:
-            assert im.n_frames == n_frames
-            assert im.is_animated == (n_frames != 1)
+@pytest.mark.parametrize(
+    "path, n_frames",
+    (
+        (TEST_GIF, 1),
+        ("Tests/images/comment_after_last_frame.gif", 2),
+        ("Tests/images/iss634.gif", 42),
+    ),
+)
+def test_n_frames(path, n_frames):
+    # Test is_animated before n_frames
+    with Image.open(path) as im:
+        assert im.is_animated == (n_frames != 1)
+
+    # Test is_animated after n_frames
+    with Image.open(path) as im:
+        assert im.n_frames == n_frames
+        assert im.is_animated == (n_frames != 1)
 
 
 def test_no_change():
diff --git a/src/PIL/GifImagePlugin.py b/src/PIL/GifImagePlugin.py
index b798bb96991..5c8016839d6 100644
--- a/src/PIL/GifImagePlugin.py
+++ b/src/PIL/GifImagePlugin.py
@@ -183,8 +183,6 @@ def _seek(self, frame, update_image=True):
         if not s or s == b";":
             raise EOFError
 
-        self.__frame = frame
-
         self.tile = []
 
         palette = None
@@ -283,6 +281,8 @@ def _seek(self, frame, update_image=True):
         if interlace is None:
             # self.__fp = None
             raise EOFError
+
+        self.__frame = frame
         if not update_image:
             return